The conventional vane-type rotary compressor works by the use of a centrifugal force on each vane which is mounted slidably on the rotor. During the rotating, the outer edge of the vanes is outwardly forced against the inner surface of the cylinder and moves in a high speed. If there is without lubricant, the vanes in such high rotating speed will be immediately damaged. Such prior system is as the U.S. Pat. No. 4,877,384.